1. Field of the Invention
The invention disclosed and claimed herein generally pertains to a method for a computer system that comprises multiple partitions, wherein a switch having multiple adapters is also provided to connect the computer system to the Ethernet or other external network. More particularly, the invention pertains to a method for the above configuration, wherein the method dynamically allocates the adapters to channels for carrying traffic between system partitions and the switch. Even more particularly, the invention pertains to a method of the above type wherein the adapters are selectively assigned to and released from respective channels, in order to improve utilization of available network bandwidth.
2. Description of the Related Art
There is currently a strong demand for high-end computer systems that can provide great flexibility. Systems of this type include for example the Central Electronic Complex (CEC), a product of International Business Machines Corporation (IBM), which is partitioned to include multiple multichip-based processing units. In such systems, administrators seek increasing ability to manage precious system resources such as network bandwidth.
In partitioned systems of the above type, it is common to provide access to an external network by means of a switch having multiple network adapters. Each adapter is associated with a corresponding port included in the switch, and the adapters are used in establishing channels between the switch and respective system partitions. If the network is an Ethernet network, the adapters are referred to as Ethernet adapters, and established channels comprise EtherChannels.
Moreover, in using a computer system of the above type, it is common to configure a Hardware Management Console (HMC) to manage the system. The HMC can also be used by a system administrator to form channels for the partitions from the adapters. In other cases, other control hosts like Integrated Virtualization Manager (IVM) can be used to set up EtherChannels. In some other cases (for example IBM AIX and Virtual I/O Server, administrator can use Operating System facilities to create EtherChannels. More particularly, taking advantage of currently available network port aggregation technologies, such as EtherChannel or IEEE 802.3ad Link Aggregation, several Ethernet adapters can be aggregated together to form a single pseudo Ethernet device. For example, two actual or physical Ethernet adapters, identified as ent0 and ent1, can be aggregated into a single logical device, identified as adapter or EtherChannel ent3. The logical adapter ent3 would then be configured with an IP address, and the aggregated adapters would be considered by the system to be just one adapter. In addition, all adapters aggregated into a logical adapter, such as ent0 and ent1, are similarly treated by remote systems as if they were just one adapter. Both EtherChannel and IEEE 802.3ad Link Aggregation require support in the switch, so that the switch will be aware of which switch ports should be treated as a single port.
Adapter aggregation, as described above, is beneficial in that the network bandwidths of all adapters included in an aggregation are contained in a single network presence. Thus, if one adapter fails, network traffic is automatically sent on to the next available adapter without disruption to existing user connections. The failed adapter will later be automatically returned to service on the EtherChannel or Link Aggregation, after it recovers. Several Unix and Linux Operating Systems support EtherChannel or Link Aggregation. For example, IBM AIX and Virtual I/O Server Operating Systems running on IBM Power hardware supports creation of EtherChannels.
Notwithstanding the benefits noted above, when currently available practices are used to form EtherChannels by aggregating several adapters, the configurations that result therefore tend to be quite static. Static channel configurations, in turn, can prevent system users from optimally using the available network bandwidth. For example, a scenario can arise, due to unprecedented workload conditions or the like, wherein some partitions are not fully utilizing their available EtherChannel bandwidth. At the same time, other partitions are found to be exceeding their available total bandwidth, and are thus in need of additional bandwidth. Such situations are common in e-business, as exemplified by a system partition running a bookstore web application. Such system partition could undergo a sudden, very substantial increase in network traffic, upon the release of a popular book.
While an EtherChannel can load-balance network traffic between its own assigned Ethernet adapters, there is currently no automated mechanism available to dynamically release Ethernet adapters from one EtherChannel, and then assign them to a different EtherChannel. Moreover, there is no mechanism for taking such action based on a system-level assessment of network bandwidth utilization, or on related Rules and Policies.